This invention relates to valve train apparatus for an internal combustion engine of the type having a pre-chamber or torch-type combustion ignition. Such an engine requires three valves per cylinder: a main combustion chamber intake valve, a secondary intake valve to the pre-chamber and a conventional exhaust valve.
The invention provides valve train apparatus which permits a main intake valve rocker arm to operate in a plane positioned at an angle to the operating plane of the pre-chamber valve rocker arm. The invention further provides valve train apparatus in which lash of the pre-chamber valve is adjustable independently of the lash of the main chamber valve. The invention also provides valve train apparatus for the operation of a secondary intake valve which is economical to produce, reliable in operation and which permits flexibility in the cylinder head design.
Valve train apparatus constructed in accordance with this invention includes first and second poppet-type intake valves mounted in a cylinder head so the ends protrude therefrom. A first rocker arm is pivotally mounted on a fulcrum and has one end contacting the protruding end of the first valve. One end of the second rocker arm is pivotally mounted to a second fulcrum while its other end engages the protruding end of the first intake valve. An intermediate portion of the second rocker arm contacts the protruding end of the second intake valve.